QUALITY ASSESSMENT OF DRESSED CARCASSES O F PIG HYBRIDS SELECTED FOR THE HIGHER PERCENTAGE OF LEAN CUTS

The objective of the present paper was to assess the quality of dresse d carcasses of pig hybrids with different level of meat performance. T he first group of hybrids was selected consistently for the expressly meat type, the other was a commonly produced hybrid SLOVHYB-1. During the experiment the pigs were housed in group pens and received a unifo rm feed mash (crude protein content 15.4%, lysine content 0.86% and en ergy content 13.0 MS). The ira vivo percentage of muscle was determine d instrumentally a day before slaughter. Dissection of carcasses was d one on the second day after slaughter in both groups of pigs under inv estigation to determine the portions of valuable lean cuts (percentage s of neck, shoulder, loin and ham with bones weight out of the weight of the side of pork after cooling), followed by detailed dissection in to basic tissues (meat, fat, bones, skin). Detailed dissection was don e in all body parts, except the head with jowl and trotters. Tab. I sh ows the indicators of carcass value of pig hybrids of both groups. The first group of hybrids, bred for the expressly meat type, had these v alues of the percentage of valuable lean cuts (VLC) and lean meat cont ent in vivo and/or post mortem: 51.25%, 54.10% and/or 56.85%. The indi cators of carcass value in the control group of slaughter hybrids were as follows: 45.58%, 50.43%. and 51.27%. Tab. II shows the relations o f the investigated indicators of carcass value to the percentage of VL C and/or muscle. A comparison of the closeness of the relations betwee n VLC percentage and muscle percentage on the one hand and other carca ss indicators on the other revealed the higher values of correlations in the first group evaluated. Therefore we believe that when the relat ions among all the carcass indicators are determined and their correct interpretation is sought for, it will be necessary to take into accou nt the level of meatiness and/or the production type of pigs. Signific ant correlations with carcass meatiness were observed in backfat area above m.l.d. and/or the ratio of m.l.d. area to backfat area above m.l .d. at the level of the last rib (r greater than or equal to 0.80), an d these values were higher than the level of correlation between m.l.d area and muscle percentage. Hence a possibility of determining the ar eas m.l.d and/or backfat by an in vivo method is very important, along with the use of the determined relations for meatiness prediction par ticularly in breeding pigs. Tab. III shows the tissue composition of c arcass parts. The largest differences in muscle percentage between the two types of hybrids were determined in neck, belly and shoulder. The re were not any statistically significant differences in meat percenta ge out of loin. The results of the experiment have revealed that the g roup of slaughter pigs of the expressly meat production type exhibited the considerably higher difference between muscle percentage and VLC percentage (+5.6%) in comparison with the hybrids of the other evaluat ed group (+2.7%). The above data document that pig selection on the ba sis of VLC percentage is less useful in the meat types of pigs as the differences in total muscle percentage are not taken account in a sati sfactory way.